Subject: RE: Solicit comments on draft-pashby-ipv6-network-discovery-00.txt

From: "Pashby, Ronald W CTR NSWCDD-B35" <[email-masked]>
Date: Fri, 23 Sep 2005 07:30:51 -0500

There are many networks that devices do not through routers. So asking the router for their addresses is not sufficient.

-----Original Message-----
From: Pekka Savola [mailto:[email-masked]]
Sent: Friday, September 23, 2005 4:38
To: Pashby, Ronald W CTR NSWCDD-B35
Cc: Jari Arkko; [email-masked]
Subject: RE: Solicit comments on
draft-pashby-ipv6-network-discovery-00.txt

On Wed, 21 Sep 2005, Pashby, Ronald W CTR NSWCDD-B35 wrote:
>> 2) Requiring all nodes implement Inverse Neighbor Discover with the
>> addidtion of the response holdoff timer.
>>
> The feature exists. But an all-nodes mandatory implementation
> requirement is additional functionality, and I'm not sure
> there's justification for that yet - but I admit that I did not
> follow the discussion in the last meeting about this, so
> I may be missing something. One approach would be
> to publish INDbis spec, but not make it mandatory for
> everyone.

As Jari said, I do not think adding mandatory-to-implement mechanisms 
solves the problem.  A solution already exists (to a degree), but the 
vendors have voted with their feet (i.e., nobody actually wants the 
feature).

In more general, I do not see sufficiently strong justification for 
this approach.  A typical operational approach in scenarios like these 
is to collect the source IP addresses which send traffic at routers 
(e.g., with logging access lists or netflow).

That approach can reliably identify any active node in the network -- 
mechanisms which rely on active probing (e.g., pings) will never be 
able to find all the nodes anyway (e.g., because the hosts may filter 
out pings in their local firewalls).

So, if you'd want to pursue the work on discovering the hosts in the 
network, I'd put a lot more emphasis on describing why exactly this is 
needed ("problem statement") and particularly why the existing 
operational techniques are not sufficient.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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From: Pekka Savola <[email-masked]>
Date: Mon, 26 Sep 2005 08:52:37 +0300 (EEST)

On Fri, 23 Sep 2005, Pashby, Ronald W CTR NSWCDD-B35 wrote:
> There are many networks that devices do not through routers. So 
> asking the router for their addresses is not sufficient.

So, in these cases using the link-local all-hosts multicast address 
should be fine?